Detent



Oct. 27, 1964 o. 1 RICE 3,153,949

o INVBNTOR ORVAI. L. RICE to lBY ATTORNEYS O. L. RICE Oct. 27, 1964 DETENT 2 Sheets-Sheet 2 Filed May l0, 1961 INVENT OR ORVAL L. RICE .,ggu/

ATTORNEYS United States Patent Oiiice 3,153,949 Patented Oct. 27, 1964 3,153,949 DETENT Orval L. Rice, Scotts, Mich., assigner to The New York Air Brake Company, a corporation of New Jersey Filed May 10, 1961, Ser. No. 169,164 3 Claims. (Cl. 74-527) This invention relates to detents.

The object of the invention is to provide an impositivo detent for a moving part that can be overridden manually and released by a fluid pressure motor operating in response to a fluid pressure signal.

The preferred embodiment is described below in connection with the accompanying drawing in which:

FIG. l is a diagram of the hydraulic system of a loader showing the improved detent in association with each oi the two sliding plungers of the directional control valve.

FIG. 2 is an enlarged sectional view of a portion of FIG. 1 showing the details of the two detents.

As shown in the drawing, the hydraulic system comprises a pump and sump 1 and 2, respectively, and a directional control valve 3 which is arranged to control the hoist and tilt motors 4 and 5, respectively, connected with the bucket 6 of the loader. The directional control valve 3 is conventional and includes a housing containing inlet and exhaust ports 7 and 8 which are connected with the pump 1 and sump 2, respectively, two motor chambers 9 and 11 which are connected with the opposite sides of tilt motor via conduits 12 and 13, and two motor chambers 14 and 15 which are connected with the opposite sides of hoist motor 4 via conduits 16 and 17. Flow to and from motor chambers 9 and 11 is controlled by a three-position hollow valve plunger 18 that is biased to the neutral or hold position shown in the drawing by centering spring 19 and is shii'table in opposite directions from that position to selectively connect one of the chambers 9 and 11 with inlet port 7 and the other of said chambers with the exhaust port 8. A four-position hollow valve plunger 21, having a centering spring 22, controls flow to and from motor chambers 14 and 15. This plunger 21 has the same three positions as plunger 18 and, in addition, has a oat position in which the motor chambers 14 and 15 and the inlet and exhaust ports 7 and 8 are interconnected.

At their left ends, the value plungers 18 and 21 are provided with the detents 23 and 23 of the present invention. As shown in FIG. 2, detent 23 comprises an outer circular sleeve 24 that is attached to the housing of the directional control valve and contains a collar 25 that is seated on snap ring 26. An inner coaxial circular sleeve 27 is guided for sliding movement within the outer sleeve 24 and the collar 25; the outer periphery of sleeve 27 containing an annular groove 28 that separates the large diameter portion 29 that iits outer sleeve 24 from the small diameter portion 31 that its the skirt 32 of collar 25. A central cylindrical member 33, threaded into the left end of plunger 18, reciprocates within inner sleeve 27 and is spaced radially from the skirt 32 to deiine an intervening annular space for receiving a circular series of detent balls 34. The annular ballreceiving space is bounded on its sides by the opposed frusto-conical surfaces 35 and 36 carried by collar 25 and sleeve 27, respectively, and these surfaces constitute cams that urge the balls 34 radially inward. The inner sleeve 27 and the balls 34 are biased toward the collar 25 by a coil spring 37. This spring is mounted in an annular space between sleeves 24 and 27 and is seated on a disc 38 that is held in place by a snap ring 39. The central member 33 is formed with a reduced diameter ball-receiving portion 41 so positioned that it is brought into alignment with the series of balls 34 when plunger 18 is in one of its operative positions. A pair of resilient O-rings 42 carried in annular grooves formed in inner sleeve 27 and a similar O-ring 4t) carried in an annular groove formed in collar 25 isolate groove 28 from the interior of outer sleeve 24. An inlet passage 43 leads through sleeve 24 in the region of groove 28.

Detent 23 is constructed in the same manner, but in this case central member 33 is connected with the plunger 21 through a universal joint 44, and is formed with a second reduced diameter ball-receiving portion 45. This portion 45 is so positioned that it is brought into alignment with the balls 34 when plunger 21 is in its float position. Another diierence between the two detents concerns the provision of a relief valve 46 in the inlet passage 43 and the addition of a restricted vent passage 47.

When the hollow plunger 18 is shifted to the right against the bias of centering spring 19 from the hold position to the position in which motor chambers 9 and 11 are connected with inlet and exhaust ports 7 and 8, respectively, ball-receiving portion 41 is brought into alignment with the series ot detent balls 34. Under the action or" spring 37 and the cam surfaces 35 and 36 on collar 25 and sleeve 27, the balls 34 are now moved radially inward into the portion 41 thereby holding the plunger 18 in this position against the centering force of spring 19. At this time, groove 28 is vented to sump 2 via inlet passage 43, conduit 43, shuttle valve 49 and conduit 51. High pressure iluid delivered to the rod end of tilt motor 5 through conduit 12 causes the motor to move the bucket 6 in the clockwise direction about its pivot 52. When `the bucket 6 reaches a predetermined position, cam 53 shifts shuttle valve 49 upward thus interrupting the vent path and allowing high pressure uid to iiow from conduit 12 to inlet passage 43 through conduit 48. This uid flows into groove 28 where, because of the diierence in the diameters of portions 29 and 31, it develops a force that shifts inner sleeve 27 to the left against the bias of spring 36. This movement of sleeve 27 releases the balls 34 and allows centering spring 19 to return plunger 18 to the hold position.

Movement of plunger 18 to the left from the hold position to its other operative position connects chambers 9 and 11 with exhaust and inlet ports 8 and 7, respectively. Motor 5 now moves the bucket 6 in a counterclockwise direction about pivot 52 and shuttle valve 49 shifts downward to vent groove 28 again. Inner sleeve 27 now assumes the FIG. 2 position. Since this operative position of plunger 18 is not a detented position, the balls 34 simply rest on the outer surface of central member 33. As soon as the operator releases plunger 18, centering spring 19 returns it to hold position.

In order to raise the bucket 6, plunger 21 is shifted to the right from the neutral position to the position in which motor chambers 14 and 15 are connected with the inlet and exhaust ports 7 and S, respectively. As in the case of the plunger 18, this movement brings ball-receiving portion 41 into aligmnent with balls 34 thus permitting the balls to move radially inward and hold the plunger in the operative position against the bias of centering spring 22. High pressure fluid now is delivered to the head end of hoist motor 4 via conduit 16 and causes the motor to raise the bucket 6. The inlet passage 43 of detent 23' is in continuous communication with conduit 16 and so, when motor 4 reaches the end of its stroke and the supply pressure rises, relief valve 46 opens and permits huid to iiow to sump 2 through passage 43', restricted passage 47 and conduit 54. This ilow develops a back pressure in groove 28 that, because of the difference in the cross-sectional areas of portions 29' and 31', produces a force that shifts inner sleeve 27 to the left. This action releases the balls 34' and permits centering spring 22 to return plunger 21 to the hold position. The pressure in groove 28'- is now dissipated through restricted passage 47 and sleeve 27' is allowed to return to the illustrated position.

Movement of plunger 21 to the left to the bucket- 'lowering position in which chambers 14and 15 are connected with the .exhaust and inlet ports 8 and 7, respectively, brings the'ball-receiving portion 45 close to, but not inV alignment with, balls.34. Since this position is not a detented position, the operator must continue to exert a holding force on the plunger. When the plunger 21 is moved further to the left to the float position, portion 45 is brought into alignment with balls 34l and, as in fthe case of the raise position, the balls move radially inward and hold Vthe plunger in that position against the centering force of spring 22. Sincethe pressure developed in conduit 16 during operation under float conditions is not high enough to open relief valve Y46, the detent 23 must be overridden manually before plunger 21 can be returned to the hold position. It willbeobvious that manual override is possible in the other detented position of plunger 21 and in the detented position of plunger 18.

While the collar 25 in the preferred embodiment is a separate part, it will` be apparent that since during operation there is no relative movement between it and sleeve 24, the collar, or at least its skirt 32, may be formed in one piece with the sleeve. The illustrated construction is preferred because it simplifies manufacture and also it facilitates changing the differential Aarea on which the detent unlatching pressureacts. Y

As stated previously, the drawing and description relate only to the preferred embodiment ofthe invention. Since many changes can be made in the structure of this embodiment Without departing from the inventive concept, the following claims should provide the sole measure of the scope of the invention.

What is claimed is:

1. A detent comprising outer sleeve means carrying an inside surface that is divided by a step into large and small diameter portions; a coaxial inner sleeve guided for sliding movement in and longitudinally of the outer sleeve means and having a step on its outer periphery that defines large and small diameter portions that lit ythe Ycorresponding portions carried by the outer'sleeve means;

a central member coaxial with and movable longitudinally of the'inner sleeve, the outer surface of the member, for at least a portion of its length, being spaced radially from the inside surface of the'outer sleeve( means to denne an intervening annular space; a circular series of balls located in said annular space; a pair of opposed cam surfaces, one carried by the end of the small diameter portions of the inner sleeve and the other carried by the outer sleeve means, the cam surfaces abutting opposite sides of the balls and being aranged tol urge .the balls radially inward rtoward the central member; at least one ballreceiving recess formed in the outer surface Yof the central member; a spring reacting between the inner sleeve is a coil spring coaxial with the sleeves and located in the second annular space between them.

3. A detent comprising an outer circular sleeve; a circular collar located within and xed to the outer sleeve, the collar having a longitudinally extending annular skirt that flits 'the outer sleeve and terminates at an inwardly directed frusto-conical cam surface; an inner coaxial circular sleeve guided for sliding movement in the outer sleeve and the skirt of the collar, the inner sleeve having a large diameter r`portion'that lits the outer sleeve and a small diameter portion that lits the skirt; an inwardly directed frustroconical cam surface carried by the small diameter end of the inner sleeve; a central Lcircular cylindrical member coaxial Vwith and slidable relatively to the inner and outer sleeves and the collar; a circular series of balls surrounding the central member and positioned between and in engagement with the cam surfaces on the inner sleeve and the collar; a reduced diameter ball-receiving portion carried by the central member and arranged to be brought into alignment with the series of balls at some point in the travel of that member; an annular chamber dened by the outer periphery of the inner sleeve and the inner periphery of the outer sleeve; a coil spring located in the annular chamber and reacting between the two sleeves to urge the inner sleeve toward the series of balls; a iluid inlet passage opening through the wall of the outer sleeve at the junction of the large and small diameter portions of the inner sleeve; and sealing means between the inner sleeve and both the outer sleeve and the skirt and between the collar and the outer sleeve for isolating a region in the outer sleeve around said junction of the small and large diameter portions from the remainder of the interior of the outer sleeve.

' References Cited in the le of this patent UNITED STATES PATENTS 

1. A DETENT COMPRISING OUTER SLEEVE MEANS CARRYING AN INSIDE SURFACE THAT IS DIVIDED BY A STEP INTO LARGE AND SMALL DIAMETER PORTIONS; A COAXIAL INNER SLEEVE GUIDED FOR SLIDING MOVEMENT IN AND LONGITUDINALLY OF THE OUTER SLEEVE MEANS AND HAVING A STEP ON ITS OUTER PERIPHERY THAT DEFINES LARGE AND SMALL DIAMETER PORTIONS THAT FIT THE CORRESPONDING PORTIONS CARRIED BY THE OUTER SLEEVE MEANS; A CENTRAL MEMBER COAXIAL WITH AND MOVABLE LONGITUDINALLY OF THE INNER SLEEVE, THE OUTER SURFACE OF THE MEMBER, FOR AT LEAST A PORTION OF ITS LENGTH, BEING SPACED RADIALLY FROM THE INSIDE SURFACE OF THE OUTER SLEEVE MEANS TO DEFINE AN INTERVENING ANNULAR SPACE; A CIRCULAR SERIES OF BALLS LOCATED IN SAID ANNULAR SPACE; A PAIR OF OPPOSED CAM SURFACES, ONE CARRIED BY THE END OF THE SMALL DIAMETER PORTIONS OF THE INNER SLEEVE AND THE OTHER CARRIED BY THE OUTER SLEEVE MEANS, THE CAM SURFACES ABUTTING OPPOSITE SIDES OF THE BALLS AND BEING ARRANGED TO URGE THE BALLS RADIALLY INWARD TOWARD THE CENTRAL MEMBER; AT LEAST ONE BALLRECEIVING RECESS FORMED IN THE OUTER SURFACE OF THE CENTRAL MEMBER; A SPRING REACTING BETWEEN THE INNER SLEEVE AND OUTER SLEEVE MEANS AND URGING THE INNER SLEEVE IN THE DIRECTION OF THE BALLS; AND A FLUID INLET PASSAGE COMMUNICATING WITH THE STEPS. 